Diethyl Phthalate
DEP
What it is
An endocrine-disrupting plasticizer and solvent (CAS 84-66-2) used in fragrance formulas. The primary phthalate still used in US cosmetic fragrances, not required to appear on the label.
In this product: Fragrance solvent/fixative, hidden inside the 'Fragrance' entry on the label.
Dose & route, what actually matters
Dermal absorption and inhalation (aerosolized mist during spray application). The inhalation route bypasses liver first-pass metabolism and may deliver DEP systemically more efficiently than dermal absorption alone.
EUROPEAN UNION
DEP itself is not banned in EU cosmetics (unlike DEHP and DBP, which are in Annex II). However, EU requires individual disclosure of 82 fragrance allergens on labels, the allergen transparency structure that the DEP disclosure gap exists within. Washington State banned ortho-phthalates in cosmetics effective January 1, 2025 (TFCA 2023).
UNITED STATES
Permitted. Under the US Fair Packaging and Labeling Act, DEP hidden inside 'Fragrance' need not be individually disclosed on US cosmetic labels. FDA 2010 survey detected DEP in fragrance products at up to 40,000 ppm.
The evidence
FDA 2010 survey of cosmetic products for phthalate content: DEP detected at concentrations up to 40,000 ppm (e.g., Navy cologne). 'DEP appears to be the only phthalate still commonly used in cosmetics.'
regulatory · 2010 · source
2015 screening of 47 branded perfumes: DEP mean 1,621 ppm, maximum 23,649 ppm. 'The use of DEP in the perfume industry is a concern as it has been identified as an endocrine disruptor.'
review · 2015 · source
California Prop 65: DEP itself is not listed on Prop 65. DEHP (a different phthalate, banned in EU cosmetics) is listed as a reproductive toxicant.
How to avoid it
Choose fragrance-free products, or brands that fully disclose their fragrance components. 'Phthalate-free' as a label claim specifically for DEP is unverifiable without full fragrance disclosure.
Where it hides
Editorial analysis of publicly available regulatory and peer-reviewed sources. Not medical advice. We name our evidence and link it, including when an ingredient is fine.